What is the procedures for selection of a surge arrestor ?
In our surge protection range we have three types of Surge Protection Devices as below :
a) Type 1 surge arrestor
> The Type 1 surge arrester is recommended for electrical installations in the service sector and industrial buildings
protected by a lightning conductor or by a meshed cage.
> It protects electrical installations against direct lightning strikes.
> It is used to conduct the direct lightning current, propagating from the earth conductor to the network conductors.
> It must be installed with an upstream disconnection device, such as a fuse or circuit breaker, whose breaking capacity
must be at least equal to the maximum prospective short-circuit current at the installation point.
> The Type 1 range of surge arresters meets the normative withstand capability of current wave type
> It is suitable for use with TT, TN-S, TN-C and 230 V IT earthing connection systems (neutral point connection).
b) Type 2 surge arrestor
> Type 2 surge arresters are installed downstream of type 1 lightning arresters in main distribution boards or sub-distribution boards.
> Type 2 surge arresters are tested with a 8/20 μs current wave.
> Discharges currents from indirect lightning strikes, inductive, conductive over voltages and switching transients.
c) Type 3 Surge arrestor
> The type 3 is for sensitive equipments.
> It corresponds to the secondary protection in our type 2 surge arresters if Up of incoming surge arrester > 1,5kV
or/and the distance between the incoming surge arrester and loads > 30m.
> These surge arresters ensures secondary protection of loads to be protected and is placed in cascade with the incoming
> Type 3 surge arresters are tested with a 12/50 μs and 8/20 μs combined wave.